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A034887
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Number of digits in 2^n.
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7
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1, 1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 6, 6, 6, 7, 7, 7, 7, 8, 8, 8, 9, 9, 9, 10, 10, 10, 10, 11, 11, 11, 12, 12, 12, 13, 13, 13, 13, 14, 14, 14, 15, 15, 15, 16, 16, 16, 16, 17, 17, 17, 18, 18, 18, 19, 19, 19, 19
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,5
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LINKS
| Eric Weisstein's World of Mathematics, Mersenne Number
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FORMULA
| a(n) = floor(n*ln(2)/ln(10)) + 1. E.g. a(10)=4 because 2^10=1024 and floor(10*ln(2)/ln(10)+1=3+1=4 - Jaap Spies (j.spies(AT)hccnet.nl), Dec 11 2003
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MAPLE
| seq(floor(n*ln(2)/ln(10))+1, n=0..100); (from J. Spies)
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MATHEMATICA
| Table[Length[IntegerDigits[DivisorSigma[w, 2]]], {w, 0, 63}] - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Mar 25 2007
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CROSSREFS
| Cf. A055253, A055254.
Sequence in context: A026819 A137214 A081832 * A082964 A099741 A047743
Adjacent sequences: A034884 A034885 A034886 * A034888 A034889 A034890
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KEYWORD
| nonn,base,easy
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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